Installation assemblies for pipeline liners, pipeline liners and methods for installing the same

Abstract

An installation assembly for installing a liner in a pipeline comprises an inner bladder having an installation end and a retrieval end. An outer bladder surrounds the inner bladder. The ends of the inner and outer bladders are coupled together adjacent the installation end. The inner bladder is coupled to an air source at a retrieval end and the outer bladder adjacent the retrieval end is free. Following installation and curing of the liner, the bladder assembly is retrieved by pulling on the retrieval end of the inner bladder, and upon retrieval, the outer bladder is inverted.

I claim:  
     
       1. An installation assembly for installing a liner in a pipeline, said installation assembly comprising: 
       a bladder assembly to be inserted into a liner, said bladder assembly including:  
       an inflatable inner bladder having an installation end and a retrieval end and defining an internal reservoir; and  
       an outer bladder surrounding said inner bladder at least along a portion of the length thereof, said outer bladder having an end coupled to said inner bladder adjacent said installation end;  
       a fluid passage coupled to said inner bladder, said fluid passage for introducing fluid into said internal reservoir to inflate said inner bladder and expand a liner carried by said bladder assembly so that said liner can be brought into firm contact with an interior surface of said pipeline; and  
       a retrieval line for removing said bladder assembly from said pipeline, said retrieval line being coupled to the retrieval end of said inner bladder so that when said bladder assembly is removed from said liner with said inner bladder deflated, said outer bladder separates from said liner and inverts.  
     
     
       2. An installation assembly according to  claim 1  further comprising an inversion element received by said inner bladder and said outer bladder adjacent said installation end, said inner and outer bladders being coupled to a portion of said inversion element. 
     
     
       3. An installation assembly according to  claim 2  further comprising an installation cable coupled to said inversion element external to said bladder assembly, said installation cable being used to pull said bladder assembly to a desired location within said pipeline. 
     
     
       4. An installation assembly according to  claim 3  wherein said inversion element is in the form of an I-section having a pair of blocks joined by a bight, said inner and outer bladders being clamped to said bight, said installation cable being coupled to one of said blocks. 
     
     
       5. An installation assembly according to  claim 1  wherein said outer bladder extends generally the entire length of said inner bladder. 
     
     
       6. An installation assembly according to  claim 1  wherein said fluid passage is a hose coupled to the retrieval end of said inner bladder, said hose constituting said retrieval line. 
     
     
       7. An installation assembly according to  claim 6  further comprising an air pump coupled to said hose to inflate and evacuate said inner bladder. 
     
     
       8. A method of installing a liner in a pipeline comprising the steps of: 
       pulling a bladder assembly carrying a wetted liner in one direction into position in said pipeline, said bladder assembly including an inner bladder having an installation end and a retrieval end and an outer bladder surrounding said inner bladder and contacting an inner surface of said liner, said outer bladder having one end coupled to said inner bladder adjacent said installation end and an opposite free end;  
       introducing fluid into said inner bladder to inflate said inner bladder so that said bladder assembly expands to bring said liner into firm contact with an interior surface of said pipeline;  
       maintaining said bladder assembly in an inflated condition for a time period sufficient for said liner to cure;  
       deflating said inner bladder; and  
       retrieving said bladder assembly from said pipeline by pulling said bladder assembly in an opposite direction via said inner bladder so that when said inner bladder moves out of said liner, said outer bladder separates from said liner and inverts.  
     
     
       9. The method of  claim 8  further comprising the steps of providing an inversion element adjacent said installation end to which said inner bladder and outer bladder are clamped and using said inversion element as a hitch to perform the pulling in said one direction. 
     
     
       10. The method of  claim 9  wherein said fluid is introduced into said inner bladder via a hose and wherein said hose is used to perform the pulling in said opposite direction. 
     
     
       11. An installation assembly for installing a liner at a junction between a main pipe and a lateral pipe, said installation assembly comprising: 
       an inflatable bladder assembly for carrying a liner, said bladder assembly including a main portion and a lateral portion and defining an internal reservoir, said lateral portion including an inner bladder and an outer bladder, said outer bladder extending at least along a portion of the length of said inner bladder, said outer bladder and inner bladder being coupled adjacent a distal end of said lateral portion; and  
       a fluid passage coupled to said bladder assembly to introduce fluid into said internal reservoir and inflate the main and lateral portions of said bladder assembly thereby to expand said liner so that when said lateral portion extends into said lateral pipe and said main portion is in said main pipe, said liner is brought into contact with the interior of said main and lateral pipes and conforms to the shape of said junction.  
     
     
       12. An installation assembly according to  claim 11  further comprising a carrier coupled to the main portion of said bladder assembly. 
     
     
       13. An installation assembly according to  claim 12  wherein said outer bladder extends partially along the length of said inner bladder. 
     
     
       14. An installation assembly according to  claim 12 , further comprising an inversion element received by said inner bladder and said outer bladder adjacent said distal end, said inner and outer bladders being coupled to a portion of said inversion element. 
     
     
       15. An installation assembly according to  claim 14  further comprising a first installation cable coupled to said inversion element external to said lateral portion, said first installation cable being used to pull said lateral portion into said lateral pipe. 
     
     
       16. An installation assembly according to  claim 15  wherein said inversion element is in the form of an I-section having a pair of blocks joined by a bight, said inner and outer bladders being clamped to said bight, said installation cable being coupled to one of said blocks. 
     
     
       17. An installation assembly according to  claim 15  wherein said carrier extends through said main portion, said installation system further comprising a second installation cable coupled to a leading edge of said carrier and a retrieval cable coupled to a trailing edge of said carrier. 
     
     
       18. An installation assembly according to  claim 17  wherein said main portion of said bladder assembly includes a single bladder in fluid communication with said inner bladder. 
     
     
       19. An installation assembly according to  claim 18  wherein said fluid passage is a hose having one end received by said carrier and being in fluid communication with said single bladder. 
     
     
       20. An installation assembly according to  claim 19  further comprising an air pump coupled to another end of said hose. 
     
     
       21. A method of installing a liner having main and lateral portions at a junction between main and lateral pipes, said method comprising the steps of: 
       pulling a bladder assembly carrying a wetted liner into said pipeline, said bladder assembly including a main portion and a lateral portion and defining an internal reservoir, said bladder assembly being positioned so that the lateral portion thereof extends into said lateral pipe and with the main portion thereof positioned in said main pipe, said lateral portion including an inner bladder and an outer sleeve surrounding said inner bladder;  
       introducing fluid into said bladder assembly to inflate said bladder assembly so that said bladder assembly expands to bring said liner into firm contact with interior surfaces of the main and lateral pipes and conform said liner to the shape of said junction;  
       maintaining said bladder assembly in an inflated condition for a time period sufficient for said liner to cure;  
       deflating said bladder assembly; and  
       retrieving said bladder assembly from said pipeline by pulling said bladder assembly from said liner, wherein when said bladder assembly is retrieved, said outer sleeve inverts.  
     
     
       22. The method of  claim 21  wherein during said retrieving, said bladder assembly is pulled in a direction opposite to that during said pulling. 
     
     
       23. A bladder assembly for installing a liner within a pipeline comprising: 
       an elongate bladder defining an internal reservoir and having a leading end and a trailing end;  
       a valve element coupled to said elongate bladder to permit the ingress and degress of fluid into said bladder thereby to inflate and deflate said bladder;  
       a sleeve generally surrounding said bladder, said sleeve being coupled to said bladder adjacent said leading end; and  
       an inversion element partially received by said sleeve and bladder adjacent said leading end.  
     
     
       24. A bladder assembly according to  claim 23  wherein said sleeve and bladder are clamped to a portion of said inversion element. 
     
     
       25. A bladder assembly according to  claim 24  wherein said valve element is coupled to said bladder at said trailing end. 
     
     
       26. A bladder assembly according to  claim 25  wherein an external portion of said inversion element defines a hitch for a cable.